Horse Sedative Use Among Humans Spreads in Deadly Mixture of ‘Tranq’ and Fentanyl

TREASURE ISLAND, Fla. — Andrew McClave Jr. loved to lift weights. The 6-foot-4-inch bartender resembled a bodybuilder and once posed for a photo flexing his muscles with former pro wrestler Hulk Hogan.

“He was extremely dedicated to it,” said his father, Andrew McClave Sr., “to the point where it was almost like he missed his medication if he didn’t go.”

But the hobby took its toll. According to a police report, a friend told the Treasure Island Police Department that McClave, 36, suffered from back problems and took unprescribed pills to reduce the pain.

In late 2022, the friend discovered McClave in bed. He had no pulse. A medical examiner determined he had a fatal amount of fentanyl, cocaine, and xylazine, a veterinary tranquilizer used to sedate horses, in his system, an autopsy report said. Heart disease was listed as a contributing factor.

McClave is among more than 260 people across Florida who died in one year from accidental overdoses involving xylazine, according to a Tampa Bay Times analysis of medical examiner data from 2022, the first year state officials began tracking the substance. Numbers for 2023 haven’t been published.

The death toll reflects xylazine’s spread into the nation’s illicit drug supply. Federal regulators approved the tranquilizer for animals in the early 1970s and it’s used to sedate horses for procedures like oral exams and colic treatment, said Todd Holbrook, an equine medicine specialist at the University of Florida. Reports of people using xylazine emerged in Philadelphia, then the drug spread south and west.

What’s not clear is exactly what role the sedative plays in overdose deaths, because the Florida data shows no one fatally overdosed on xylazine alone. The painkiller fentanyl was partly to blame in all but two cases in which the veterinary drug was included as a cause of death, according to the Times analysis. Cocaine or alcohol played roles in the cases in which fentanyl was not involved.

Fentanyl is generally the “800-pound gorilla,” according to Lewis Nelson, chair of the emergency medicine department at Rutgers New Jersey Medical School, and xylazine may increase the risk of overdose, though not substantially.

But xylazine appears to complicate the response to opioid overdoses when they do happen and makes it harder to save people. Xylazine can slow breathing to dangerous levels, according to federal health officials, and it doesn’t respond to the overdose reversal drug naloxone, often known by the brand name Narcan. Part of the problem is that many people may not know they are taking the horse tranquilizer when they use other drugs, so they aren’t aware of the additional risks.

Lawmakers in Tallahassee made xylazine a Schedule 1 drug like heroin or ecstasy in 2016, and several other states including Pennsylvania, Ohio, and West Virginia have taken action to classify it as a scheduled substance, too. But it’s not prohibited at the federal level. Legislation pending in Congress would criminalize illicit xylazine use nationwide.

The White House in April designated the combination of fentanyl and xylazine, often called “tranq dope,” as an emerging drug threat. A study of 20 states and Washington, D.C., found that overdose deaths attributed to both illicit fentanyl and xylazine exploded from January 2019 to June 2022, jumping from 12 a month to 188.

“We really need to continue to be proactive,” said Amanda Bonham-Lovett, program director of a syringe exchange in St. Petersburg, “and not wait until this is a bigger issue.”

‘A Good Business Model’

There are few definitive answers about why xylazine use has spread — and its impact on people who consume it.

The U.S. Drug Enforcement Administration in September said the tranquilizer is entering the country in several ways, including from China and in fentanyl brought across the southwestern border. The Florida attorney general’s office is prosecuting an Orange County drug trafficking case that involves xylazine from a New Jersey supplier.

Bonham-Lovett, who runs IDEA Exchange Pinellas, the county’s anonymous needle exchange, said some local residents who use drugs are not seeking out xylazine — and don’t know they’re consuming it.

One theory is that dealers are mixing xylazine into fentanyl because it’s cheap and also affects the brain, Nelson said.

“It’s conceivable that if you add a psychoactive agent to the fentanyl, you can put less fentanyl in and still get the same kick,” he said. “It’s a good business model.”

In Florida, men accounted for three-quarters of fatal overdoses involving xylazine, according to the Times analysis. Almost 80% of those who died were white. The median age was 42.

Counties on Florida’s eastern coast saw the highest death tolls. Duval County topped the list with 46 overdoses. Tampa Bay recorded 19 fatalities.

Cocaine was also a cause in more than 80 cases, including McClave’s, the Times found. The DEA in 2018 warned of cocaine laced with fentanyl in Florida.

In McClave’s case, Treasure Island police found what appeared to be marijuana and a small plastic bag with white residue in his room, according to a police report. His family still questions how he took the powerful drugs and is grappling with his death.

He was an avid fisherman, catching snook and grouper in the Gulf of Mexico, said his sister, Ashley McClave. He dreamed of being a charter boat captain.

“I feel like I’ve lost everything,” his sister said. “My son won’t be able to learn how to fish from his uncle.”

Mysterious Wounds

Another vexing challenge for health officials is the link between chronic xylazine use and open wounds.

The wounds are showing up across Tampa Bay, needle exchange leaders said. The telltale sign is blackened, crusty tissue, Bonham-Lovett said. Though the injuries may start small — the size of a dime — they can grow and “take over someone’s whole limb,” she said.

Even those who snort fentanyl, instead of injecting it, can develop them. The phenomenon is unexplained, Nelson said, and is not seen in animals.

IDEA Exchange Pinellas has recorded at least 10 cases since opening last February, Bonham-Lovett said, and has a successful treatment plan. Staffers wash the wounds with soap and water, then dress them.

One person required hospitalization partly due to xylazine’s effects, Bonham-Lovett said. A 31-year-old St. Petersburg woman, who asked not to be named due to concerns over her safety and the stigma of drug use, said she was admitted to St. Anthony’s Hospital in 2023. The woman, who said she uses fentanyl daily, had a years-long staph infection resistant to some antibiotics, and a wound recently spread across half her thigh.

The woman hadn’t heard of xylazine until IDEA Exchange Pinellas told her about the drug. She’s thankful she found out in time to get care.

“I probably would have lost my leg,” she said.

This article was produced in partnership with the Tampa Bay Times.

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.

Subscribe to KFF Health News’ free Morning Briefing.